TITLE

Hash::Diff::Dispatch - execute code depending on difference between hashes

DESCRIPTION

Execute code based on the difference between the saved version of a hash and a new one

SYNOPSIS

 my $hash_watcher = Hash::Diff::Dispatch->new(

        {}, # Sets the starting hash
 
        # The events will be called using the order returned
        # by calling 'keys' on these values...
        
        'b' => \&bold,
        'i' => \&italic,

 );


 # Will call: bold('on', 5)
 $hash_watcher->update( { b => 5, a => 'la' } );

 # Will call: bold('changed', 6)
 $hash_watcher->update( { b => 6 } );

 # Will call: bold('changed', 0)
 $hash_watcher->update( { b => 0 } );

 # Will call: bold('off')
 $hash_watcher->update( {} );

METHODS

new

Accepts a starting hash-ref, and then a list of keys you want to watch, and the code to execute when they change. It will take a copy of the hash in the hash-ref you specify.

update

Accepts a hash-ref, which it'll take a copy of, and make it the 'saved' hash to check the next call to update again.

If a key's value has changed, it'll execute the code specified when you created the object. If the key exists where it didn't before, it'll pass 'on' as the first argument, and the new value as the second. If it's changed, 'changed' and the new value. If it's been deleted, it'll pass 'off'.

AUTHOR

Pete Sergeant - pete@clueball.com

LICENSE

As Perl.